Time-of-Flight cameras, for example, may use pixels to measure the time-of-flight of a light signal as it travels between the camera and an object, to determine a distance of the object from the camera. Multiple pixels may also be used, where light signals associated with individual pixels may provide distance measurements for discrete points on the object, forming a three-dimensional “distance image.” This can be made possible by detecting differences in the delays associated with reflected light signals off of the discrete points, for example.
Pixels can be constructed of semiconductor materials (such as silicon, germanium, indium gallium arsenide, lead sulfide, etc.), and may generate a current or voltage when exposed to a light signal. Pixels may also include capacitances (e.g., parasitic capacitances, gate capacitances, etc.) that are charged and discharged with operation of the pixel. In some cases, a pixel may be coupled to at least a pair of voltage potentials, or a voltage source and ground, for example. During operation, the capacitances may alternately charge by being coupled to a higher of the voltage potentials and discharge by being coupled to a lower of the voltage potentials. In many cases, this can result in considerable power consumption or waste, particularly as the frequency of charging/discharging increases. This may be more evident, for example, in cases where a charged capacitance is discharged to ground. Further, with an array of multiple pixels, the power consumption can be multiplied.